Albert Barnes Commentary Joshua 19:50

"according to the commandment of Jehovah they gave him the city which he asked, even Timnath-serah in the hill-country of Ephraim; and he built the city, and dwelt therein." — Joshua 19:50 (ASV)

Nothing is said of any express command of God concerning the inheritance of Joshua. But as such a special portion appears to have been promised to Caleb when he and Joshua alone of the twelve spies remained faithful (Joshua 14:6–9), it is probable that a similar promise was made to Joshua.

The name of the place is also written Timnath-heres (Judges 2:9), by a transposition of the letters. The rabbinical explanation that the name Timnath-heres (that is, “portion of the sun”) was given because a representation of the sun was affixed to the tomb in memory of Joshua’s command to the sun to stand still, appears to be an afterthought. The name Timnath-serah (“portion that remains”) was perhaps given to the place because it was allotted to Joshua—the last allotment made in the entire distribution of his conquests.

The site has been conjectured to be “Tibneh,” a village about five miles northwest of Lydda (or, by Conder, Kerr Hares, nine miles south of Nablous).